SEALSQ Corp美股招股说明书(2025-10-16版)

12,640,000 Ordinary Shares of SEALSQ Corp We are offering in a registered direct offering to certain investors (the “Investors”) 12,640,000 Ordinary Shares, par valueUS$0.01 per share (our “Ordinary Shares”), at an offering price of $7.50 per share. The Ordinary Shares offered to the Investors willbe issued pursuant to this prospectus supplement, the accompanying base prospectus, and a securities purchase agreement, datedOctober 15, 2025, by and among us and the Investors (the “Securities Purchase Agreement”). See “Description of Ordinary Shares” onpage 9 of the accompanying base prospectus and page S-16 of this prospectus supplement for a more complete description of thesecurities offered hereby. In a concurrent private placement pursuant to the Securities Purchase Agreement (the “Concurrent Private Placement”), weare selling to the Investors (i) unregistered Pre-funded Warrants to purchase up to 14,026,666 Ordinary Shares (the “Pre-fundedWarrants”) and (ii) unregistered Class D Warrants to purchase up to 53,333,332 Ordinary Shares (the “Class D Warrants,” and togetherwith the Pre-funded Warrants, the “Private Warrants”). The Class D Warrants will be exercisable immediately upon issuance, and have a term of exercise of seven (7) years fromthe date of issuance, and an exercise price per share equal to $9.25. Each Pre-funded Warrant is exercisable for one Ordinary Share at$0.0001 per Ordinary Share. The Pre-funded Warrants are immediately exercisable and may be exercised at any time until all of thePre-funded Warrants are exercised in full. The Private Warrants are being offered at a combined offering price of $7.50 per Pre-fundedWarrant and accompanying Class D Warrants. The Private Warrants and the Ordinary Shares issuable upon the exercise of the PrivateWarrants are being offered pursuant to the exemption provided in Section 4(a)(2) or another exemption under the Securities Act of1933, as amended, or the Securities Act, and they are not being offered pursuant to this prospectus supplement or the accompanyingprospectus. We engaged Maxim Group LLC to act as our sole placement agent (the “Placement Agent”) in connection with this offering.The Placement Agent is not purchasing or selling any of the securities offered by us in this offering and is not required to arrange thepurchase or sale of any specific number or dollar amount of securities. Our Ordinary Shares are listed on the Nasdaq Capital Market under the symbol “LAES.” The last reported sale price of ourOrdinary Shares on the Nasdaq Capital Market on October 14, 2025 was $7.65 per Ordinary Share. We are an emerging growth company as that term is used in the Jumpstart Our Business Startups Act of 2012 and, as such,are subject to certain reduced public company reporting requirements. Investing in our securities involves a high degree of risk and uncertainty. See “Risk Factors” beginning on pageS-11of this prospectus supplement, on page 4 of the accompanying base prospectus and in the documents incorporated by referenceinto this prospectus supplement and accompanying base prospectus concerning factors you should consider before investing inour securities. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved ofthese securities or determined if this prospectus supplement or accompanying prospectus is truthful or complete. Anyrepresentation to the contrary is a criminal offense. (1)We have also agreed to reimburse the Placement Agent for certain of their offering-related expenses. See “Plan ofDistribution” for additional information regarding Placement Agent fees and estimated expenses. The delivery to purchasers of the securities offered and sold in this offering is expected to be made on or about October 16,2025, subject to satisfaction of certain customary closing conditions. MAXIM GROUP LLC Prospectus Supplement dated October 15, 2025 TABLE OF CONTENTS PROSPECTUS SUPPLEMENT ABOUT THIS PROSPECTUS SUPPLEMENTS-iiCAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTSS-1PROSPECTUS SUPPLEMENT SUMMARYS-6THE OFFERINGS-10RISK FACTORSS-11USE OF PROCEEDSS-14CAPITALIZATIONS-15DESCRIPTION OF ORDINARY SHARESS-16CERTAIN TAX CONSIDERATIONSS-17DILUTIONS-18PLAN OF DISTRIBUTIONS-20EXPENSESS-24LEGAL MATTERSS-25EXPERTSS-25ENFORCEABILITY OF CIVIL LIABILITIESS-25WHERE YOU CAN FIND MORE INFORMATIONS-25INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCES-26 PROSPECTUS ABOUT THIS PROSPECTUS1ABOUT OUR COMPANY2RISK FACTORS4FORWARD-LOOKING STATEMENTS4CAPITALIZATION7USE OF PROCEEDS8DESCRIPTION OF ORDINARY SHARES9DESCRIPTION OF WARRANTS16DESCRIPTION OF SUBSCRIPTION RIGHTS18DESCRIPTION OF UNITS19TAXATION20PLAN OF DISTRIBUTION21LEGAL MATTERS23EXPERTS23INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE23WHERE YOU CAN FIND MORE INFORMATION24ENFORCEABILITY OF CIVIL LIABILITIES24EXPENSES24 ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement and the accompanying base prospectus are part of a registration statement